Process for working up gas purifying masses



Patented June 5, 1934 1,962,051

UNHTED STATES PATENT OFFHE PROCESS FOR WORKING UP GAS EUHJIFYING MASSESJoseph-Arnold Bordo, Essen, Germany, assignor to the firm VereinigteStahlwerke Aktiengesellschaft, Dusseldorf, Germany No Drawing.Application July 8, 1932, Serial No. 621,513. In Germany July 18, 1931 1Claim. (Cl. 23228) This invention relates to a process for rewhich hasbeen freed from impurities, more covering sulfur from spent gaspurifying masses. particularly tarry constituents, for the reaction Inthe purification of large quantities of gas with the sulphur dioxide.with gas purifying masses, such considerable It is moreover advantageousto carry out the amounts of spent purifying mass are obtained reactionunder a slight pressure and whilst stirthat it appears economical towork them up for ring the liquid. the recovery of the sulphur containedtherein. Instead 'of introducing sulphuretted hydrogen In order toisolate the sulphur the masses into the solution it is also possible totreat the can be extracted with organic solvents such as solventcontaining sulphur dioxide, with an 10 carbon disulphide. In this methodof operation aqueous solution of sulphuretted hydrogen and however thesolution contains in addition to sulit is also possible in this mannerto decompose phur, organic constitutents such as for example, thesulphur dioxide completely.

tar, which contaminate the sulphur separated Ema Z 1 out during thesubsequent distillation and renmp 15- der it unsaleable. It is thereforenecessary to 250 cc. of a cloudy carbon disulphide extract remove theorganic impurities from the soluof a spent gas purifying mass, which hadan ticns and for this purpose recourse is advanintense brown colour dueto organic impurities tageously had to a treatment with sulphuric andcontained about 33% of sulphur and which acid. In such case however,small amounts of had been treated with strong sulphuric acid for .20sulphur dioxide are formed which then are the purpose of removing theorganic impurities partly transferred to the solvent; considerable wasseparated from the sulphuric acid layer quantities in fact passing overin the presence by running off the latter after stirring several ofsmall amounts of water. If the solution be times and allowing theimpurities collecting at thereupon distilled off in iron apparatus forthe bottom to settle again. The sulphuric acid 25 liberating thesulphur, the sulphur dioxide as layer can also be separated from thecarbon such, has such a powerful corrosive action on disulphide layer bydrawing off the latter, since the apparatus that it renders it uselessafter a the sulphuric acid is not completely consumed short time. in oneoperation, but can be employed several The present inventioncontemplates a process times for purification and advantageously re-.30. according to which the aforesaid drawbacks are main in thepurifying vessel. After treating the obviated. The process is based onthe fact that carbon disulphide extract with a sulphuric acid thesulphur dioxide can be removed from the the now clear and light yellowcoloured carbon extract of the purifying mass obtained with andisulphide extract contained 0.165470 sulphur organic solvent andtreated with sulfuric acid dioxide. In order to remove the sulphurdioxide -35 D I t0 distillation y decomposing it, using for the carbondisulphide extract was very intimatethis purpose an agent which attacksneither the ly mixed for a short time with 200 to 250 cc. apparatus 1101the v nt and whic doe no of a saturated aqueous solution of sulphurettedcontaminate the sulphur obtained. hydrogen. After separation of thelayers, the

In order to achieve this object according to carbon disulphide exhibiteda neutral reaction.

40 the present invention the sulfur is extracted The sulphur dioxide wascompletely decomposed by a solvent f om e as-p y mass, and and afterseparating off the layer of water, the the extracted solution is treatedwith sulphuric distillation of the carbon disulphide extract acid andthen with hydrogen sulfide to decomcould be carried out withoutdifficulty. The pose the sulfur dioxide produced during the sulphurobtained was golden yellow and odour- 45 sulfuric acid treatment. Thesulphur liberated less.

from the sulphur dioxide is then recovered to- Example 2 gether with theremaining sulphur by distilling off the solvent. Since the sulphurdioxide content of the car- It is thus possible, by means of the processbon disulphide extract treated with sulphuric 50 of the presentinvention, to recover sulphur acid can vary within rather wide limits250 ccs. from gas purifying masses economically and to of the same weremixed with 25 cos. of water in avoid corrosion diifioulties completely.order to increase its receptivity for sulphur di- Instead of employingpure sulphuretted hydrooxide. This mixture was saturated with sulphurgen, it is also possible to employ coke oven dioxide by introducing thisgas. As was ascer- 55 crude gas containing sulphuretted hydrogen, tainedby titration 1 cc. of the carbon disulment was carried out in the mannerset forth in Example 1.

A process for recovering sulfur from spent gas-purifying masses whichcomprises extracting the sulfur from the purifying mass by a solvent,treating the extracted solution with sulfuric acid, and then withhydrogen sulfide to decompose the sulfur dioxide produced during thesulfuric acid treatment.

J OSEPH-ARNOLD BORDO.

